Vehicular navigation systems and portable navigation systems and have become increasingly common. These navigation systems allow users to receive directions to different locations and may also allow users to interact with other vehicular systems, such as a climate control system or an audio system. Many vehicular navigation systems have now been configured to receive speech data and perform an action responsive to the received speech data. Hence, by speaking commands, a vehicle occupant can prompt the vehicle navigation system to find a location, such as the nearest gas station or a spoken address, or can prompt the vehicle navigation system to adjust the temperature within the vehicle or change a radio station currently played within the vehicle.
However, conventional vehicular navigation systems only recognize a specific number of predefined commands, such as “find nearest ATM” or “radio next station.” Because these predefined commands have a specific format, such as a specific grammatical format, users are required to memorize the specific format of the predefined commands to interact with a vehicular navigation system. However, many users do not have the time to review a list of the predefined commands recognized by a conventional vehicular navigation system, much less time to memorize the format of the predefined commands which are recognized by the conventional vehicular navigation system.
Because many users rely on trial and error or dealer demonstrations to learn how to use a conventional vehicular navigation system, many users do not know the commands which are recognized by the conventional vehicular navigation system and quickly become frustrated with the conventional vehicular navigation system. Despite limited training on use of a conventional vehicular navigation system, users frequently stop using the conventional vehicular navigation system if the vehicular navigation system does not work properly during initial use.
Further, because the predefined commands recognized by conventional vehicular navigation systems have a specific format and users are generally unfamiliar with the specific format expected by the vehicular navigation system, generally only half of the speech data received by the vehicular navigation system is identified as a predefined command which causes a desired action. One fourth of the speech data received by a conventional vehicular navigation system is incorrectly interpreted, causing the vehicular navigation system to perform an action other than the user-desired action or no action. The remaining one fourth of the received speech data is generally not recognized by a conventional vehicular navigation system causing no action to be taken by the vehicular navigation system. Hence, the limited ability of conventional vehicular navigation systems to identify speech data having a specific format, conventional vehicular navigation systems have high rates of classification errors or non-recognition of user provided speech data, leading to user dissatisfaction with the conventional vehicular navigation system.
Thus, what is needed is a system and method for accurately associating freeform commands with corresponding vehicle navigation commands.